jQuery.extend({
    createUploadIframe: function(id, uri){
            //create frame
            var frameId = 'jUploadFrame' + id;
            var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
            if(window.ActiveXObject){
                    if(jQuery.browser.version=="9.0" || jQuery.browser.version=="10.0"){
                            var io = document.createElement('iframe');
                            io.id = frameId;
                            io.name = frameId;
                    }else if(jQuery.browser.version=="6.0" || jQuery.browser.version=="7.0" || jQuery.browser.version=="8.0"){
                            var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
                            if(typeof uri== 'boolean'){
                                    io.src = 'javascript:false';
                            } else if(typeof uri== 'string'){
                                    io.src = uri;  
                            }  
                    }
            }
            iframeHtml += ' />';
            jQuery(iframeHtml).appendTo(document.body);
            return jQuery('#' + frameId).get(0);
    },
    createUploadForm: function(id, fileElementId, data){
            //create form
            var formId = 'jUploadForm' + id;
            var fileId = 'jUploadFile' + id;
            var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
            if(data){
                    for(var i in data){
                            jQuery('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
                    }
            }
            //single
            if(typeof(fileElementId) == 'string'){
                    fileElementId = [fileElementId];
            }
            for(var i in fileElementId){
                    var oldElement = jQuery('#' + fileElementId[i]);
                    var newElement = jQuery(oldElement).clone();
                    jQuery(oldElement).attr('id', fileId);
                    jQuery(oldElement).before(newElement);
                    jQuery(oldElement).appendTo(form);
            }
            //set attributes
            jQuery(form).css('position', 'absolute');
            jQuery(form).css('top', '-1200px');
            jQuery(form).css('left', '-1200px');
            jQuery(form).appendTo('body');
            return form;
    },
    ajaxFileUpload: function(s) {
            // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
            s = jQuery.extend({}, jQuery.ajaxSettings, s);
            var id = new Date().getTime()       
            var form = jQuery.createUploadForm(id, s.fileElementId, (typeof(s.data)=='undefined'?false:s.data));
            var io = jQuery.createUploadIframe(id, s.secureuri);
            var frameId = 'jUploadFrame' + id;
            var formId = 'jUploadForm' + id;      
            // Watch for a new set of requests
            if ( s.global && ! jQuery.active++ ){
                    jQuery.event.trigger( "ajaxStart" );
            }
            var requestDone = false;
            // Create the request object
            var xml = {};
            if ( s.global )
                    jQuery.event.trigger("ajaxSend", [xml, s]);
            // Wait for a response to come back
            var uploadCallback = function(isTimeout){
                    var io = document.getElementById(frameId);
                    var execontent = function(){
                            try
                            {  
                                    if(io.contentWindow)
                                    {
                                            xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
                                            xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;

                                    }else if(io.contentDocument)
                                    {
                                            xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
                                            xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
                                    }
                            }catch(e)
                            {
                              jQuery.handleError(s, xml, null, e);
                            }
                            if ( xml || isTimeout == "timeout"){
                                    requestDone = true;
                                    var status;
                                    try {
                                            status = isTimeout != "timeout" ? "success" : "error";
                                            // Make sure that the request was successful or notmodified
                                            if ( status != "error" )
                                            {
                                                    // process the data (runs the xml through httpData regardless of callback)
                                                    var data = jQuery.uploadHttpData( xml, s.dataType );   
                                                    // If a local callback was specified, fire it and pass it the data
                                                    if ( s.success )
                                                            s.success( data, status );
                                                    // Fire the global callback
                                                    if( s.global )
                                                            jQuery.event.trigger( "ajaxSuccess", [xml, s] );
                                            } else
                                                    jQuery.handleError(s, xml, status);
                                    } catch(e)
                                    {
                                            status = "error";
                                            jQuery.handleError(s, xml, status, e);
                                    }
                                    // The request was completed
                                    if( s.global )
                                            jQuery.event.trigger( "ajaxComplete", [xml, s] );
                                    // Handle the global AJAX counter
                                    if ( s.global && ! --jQuery.active )
                                            jQuery.event.trigger( "ajaxStop" );
                                    // Process result
                                    if ( s.complete )
                                            s.complete(xml, status);
                                    jQuery(io).unbind();
                                    setTimeout(function(){
                                            try{
                                                    jQuery(io).remove();
                                                    jQuery(form).remove();  
                                            } catch(e){
                                                    jQuery.handleError(s, xml, null, e);
                                            }
                                    }, 100);
                                    xml = null;
                            }
                    };
                    execontent();
            }
            // Timeout checker
            if ( s.timeout > 0 ){
                    setTimeout(function(){
                            // Check to see if the request is still happening
                            if( !requestDone ) uploadCallback( "timeout" );
                    }, s.timeout);
            }
            try{
                    var form = jQuery('#' + formId);
                    jQuery(form).attr('action', s.url);
                    jQuery(form).attr('method', 'POST');
                    jQuery(form).attr('target', frameId);
                    if(form.encoding)
                    {
                            jQuery(form).attr('encoding', 'multipart/form-data');
                    }else{
                            jQuery(form).attr('enctype', 'multipart/form-data');
                    }
                    jQuery(form).submit();
            } catch(e){
                    jQuery.handleError(s, xml, null, e);
            }
            jQuery('#' + frameId).load(uploadCallback );
            return {abort: function () {}}; 
    },
    uploadHttpData: function( r, type ) {
            var data = !type;
            data = type == "xml" || data ? r.responseXML : r.responseText;
            // If the type is "script", eval it in global context
            if ( type == "script" )
                    jQuery.globalEval( data );
            // Get the JavaScript object, if JSON is used.
            if ( type == "json" )
                    eval( "data = " + data );
            // evaluate scripts within html
            if ( type == "html" )
                    jQuery("<div>").html(data).evalScripts();
            return data;
    },
    handleError: function( s, xhr, status, e ){
    // If a local callback was specified, fire it  
            if ( s.error ) {
                    s.error.call( s.context || s, xhr, status, e );
            }
            // Fire the global callback  
            if ( s.global ) {  
                    (s.context ? jQuery(s.context) : jQuery.event).trigger( "ajaxError", [xhr, s, e] );
            }
    }
})